1. Field of the Invention
The present invention generally involves the field of technology pertaining to devices for exercising the human body. More particularly, the invention relates to an improved device for strengthening joints of the leg, and particularly the muscles, tendons and ligaments of the ankle joint.
2. Description of the Prior Art
It is well established that proper exercise serves to strengthen the muscles, tendons and ligaments of the human body, particularly in the areas surrounding the joints in order to prevent or rehabilitate various types of joint injuries. Different joints necessarily have different directional and angular movements which must be taken into consideration during exercise so that complete and balanced strengthening of a given joint can be fully realized.
The joints of the leg, including the knee joint and the ankle joint, are quite prone to injury. This is particularly of concern during athletic activities when an athlete imposes unusual degrees of stress to the joints from different directions which are normally not realized during nonathletic activities. Injuries sustained by the knee and ankle joints can be especially painful and debilitating because of the complex nature of these joints and the necessity for long term rehabilitation or complete recovery of such injuries.
The knee joint is substantially limited to providing pivotal movement of the lower leg with respect to the upper leg, as exemplified by the simple movement between knee extension and knee relaxation wherein the muscles of the upper leg or thigh are utilized. The ankle joint is more complex in its function since it undergoes essentially four basic movements, including planter flexion wherein the foot is rotated in a downward direction, dorsal flexion wherein the foot is rotated in an upward direction, inversion supination wherein the foot is rotated outwardly, and eversion pronation wherein the foot is rotated inwardly. These ankle movements are controlled by the muscles of the lower leg located at the front or anterior, the sides or media and lateral, and the back or posterior thereof. In order to properly strengthen the ankle joint for preventing injuries thereto or realize rapid rehabilitation of an injured ankle joint, it is necessary that all of the muscles, tendons and ligaments controlling all directions of ankle movements be directly exercised under controlled resistance conditions and resistance pressure be asserted over the planes defined by these movements.
The prior art has recognized the benefits of devices for exercising both the muscles and joints of the body wherein resistance is imparted by means of resilient members, such as springs or lengths of rubber bands. It is also known to utilize such devices for directly exercising the muscles and joints of both the upper and lower legs. Examples of devices believed to be indicative of the state of the art in this field of technology are taught by the U.S. Pat. Nos. 1,952,750 Gailey, 2,097,376 Marshman, 2,467,943 Mikell, Hinds et al 4,195,835, 4,251,070 Leseberg, and 4,478,414 Molloy.
It is well recognized that recent activity in the fields of exercising devices and sports medicine has been quite intense, particularly with regard to developments based on stringent scientific and medical considerations in order to provide optimum results. Exercising devices and related equipment are therefore being produced under high technology standards and based on sound principles of kinesiology and related factors. There has also been a recognized need for an improved device which is capable of providing full strengthening and rehabilitating effects to the muscles and joints of the leg, particularly the ankle joint, in a manner and with the results that are consistent with the high standards now expected in this field of technology.